Combined conduit clamping and bushing device



nec. z, 1930. H. R. COK 1,783,409

COMBINED CONDUIT CLAMPING AND BUSHING DEVICE Filed Feb. 23, 1929 n.. eb

Patented Dec. 2, 1930 UNITED STATES PATENT OFFICE HERBERT RAY COOK, 0F CHICAGO, ILLINOIS, ASSIGNOR TO JEFFERSON ELECTRIC COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS COMBINED CONDUIT CLAMPING AND RUSHING DEVICE Application filed February 23, 1929. Serial No. 342,122.

The invention relates generally to outlet boxes and more specifically to boxes of this character embodying means for clamping conduits entering the sides of the box and for bushing the ends of such conduits to prevent tearing of the insulation on the wires by the sharp edges of the conduit armor.

The primary object of the present invention is to simplify the manufacture and assembly of such outlet boxes by providing a unitary device for clamping and bushing the ends of a pair of conduits, which device may be economically produced and may be mounted within the box by a single easily performed operation.

Another object is to provide an outlet box having such a clamping and bushing device operable without removing any part of the device from the box to clamp and bush a pair of cables entering the box through similarly positioned lrnoclnout holes in either of two intersecting walls of the box.

Another object is to provide an outlet box having a clamping and bushing member formed from a single sheet of metal and adapted to be held in position and to be operated by a single screw to clamp a pair of cables entering the box through either of two intersecting walls.

Another object is to provide a new and iinproved device of this character having one member formed from a single piece of sheet metal with a cable-engaging portion at one edge, a bushing portion at the other edge substantially parallel to the cable-engaging portion, and a second member in the form of a screw extending through an aperture in the first member and disposed at an angle of substantially 450 to said cable-engaging. and bushing portions for supporting the first member within the box and for moving and applying clamping force to the cable-engaging portion.

Another object is to provide an outlet box having a conduit clamping and bushing member initially mounted in the box by a screw occupying a position substantially bisecting the angle between the side and base walls of the box, said member extending substantially parallel to the intersection of the two walls andhaving an aperture formed substantially centrally thereof through which the screw extends leaving its head exposed within the box and readily accessible for operation through the open side of the box, said member having a web extending from said screw toward one wall of the box with a clamping ilange at the edge of the web extending to Ward the other wall,v and a bushing portion having spaced bushing apertures therein and extending from the screw toward and into contact with the other wall to act as a bearing for the clamping member against said otherwall so that when the screw is tightened the clamping member will be caused to pivot about its p oint of cont-act with said other wall. l

Another object is to provide an outlet box of this character having a combined conduit clamping and bushing device mounted there-v in and. operable to engage and clam a conduit at a point adjacent the wall through which it projects and having a portion arranged to be positioned in the proper relation to bush the ends of such a conduit, said device being arranged to permit free transverse movement of that portionv of the conduit lying between the point of clamping and the end thereof seas to insure an effective bushing of the conduit by the device.

1 Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

- Figure l is a fragmental view looking intov the open side of an outlet box embodying the preferred form of the invention and showing a pair of conduits clamped in the box.

Fig. 2 is a fragmental sectional view taken along the line 2--2 of Fig. l.

Fig. 3 is a fragmental sectional-view taken alongthe line 3 3 of Fig. 1 looking in the direction of the arrows.

Fig. t shows a development of one of the members of the clamping and bushing device.

While I have shown in the accompanying drawings and will herein describe in detail the preferred embodiment of the invention, it is to be understood that this disclosures.

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given for the purpose ot illustrating the iuvention and represents but one specific mauner ot carrying out the invention. It is not intende-c` as a lin'iitation of the invention to the construction disclosed. In the appended claims, I aim to cover all modifications and alternative co structions falling within the scope ot the invention as limited by the state of the prior art.

In the form chosen for disclosure herein, the invention is embodied in an outlet box having` a base wall 5 and upstanding side walls G substantially at right angles to the base wall and intersecting therewith at i'. A pair ot knock-out holes 8 is formed in the side wall 6 and another pair is formed in the base wall 5 to provide optional inlets for a pair of cables or conduits each ot' which is designated by the numeral 9. These cables or conduits as herein illustrated are of the type in which a pair of wires 10 having in sulation 11 thereabout extend through a tlexible tubular conduit 12 which serves as armor to protect the wires and the insulation.

The ends of a pair of these conduits 9 with the wires 10 are inserted through one of the pairs ot knock-out holes 8, in this case through the holes in the side wall 6, so that the wires will be accessible Within the box for connection to a switch or to other wires as desired. In cutting oil the conduit armor 12 to permit the wires 10 in the insulation 11 to extend beyond the conduit, sharp cut-ting edges 13 are left exposed on the end et the conduit armor and to prevent these edges from destroying the insulation 11 and short circuiting the wires 1() it is desirable to provide means for bushing the ends of the conduit. It is also desirable to provide ,clamping); means Within the box for securing the conduits 9 in the desired relation to the box and in order to effect economy in manufacture, assembly and in the use ot boxes ot this character, the invention contemplates the provision ot a. unitary device for clampingand bushin the ends ot such conduits which extend into the box through the pair ot knock-out holes in either ot two intersecting Valls of the box.

In the preferred term illustrated herein, this unitary clamping and bushing' device comprises two members one ot which coustitutes aA screw 15 engaging` the box at the intersection 7 of the base and side walls 5 and 6 and occupyingr the position substantially bisectingthe angle between these two walls so that the head ot the screw faces outwardly toward the open face of the box in a convenient position for operation. The other meinber olI the device provides the means tor engaging' the conduits in a clamping operation and also provides means tor bushing the ends ot the conduits clamped thereby. This member is held in position and operated by the screw 15 and is preferably of such a character that it may be formed by stamping from a single sheet of sheet metal and in the form herein illustrated it comprises a member 16 which requires a substantially o rectangular sheet metal blank as will be seen in F ig. 4.

This member is bent into substantially lli-shaped cross section as is best illustrated in, Fig'. 9. so as to have a web portion l? with 7 flange 18 extending from one edge at sulastantially right angles to the web and a second tiange 19 extending` .in the same direction from the other edge ot the web. rlfhe lirst tlange 18 as herein illustrated serves as the clamping` or cable enu'agjing portion ot the member 1G and is thereiore of lees length than the flange 19 and has spaced .f ini-circular notches il() Yformed in its edges to co Atorni roughly with the sides ot a pair olE coinluit: g5 for preventing transverse displacement of such conduits when they are clamped thereby.

rlhe second liang'e 19 serves as the bushing portion of the niefnher 16 and tor this p urY pose a pair ot spaced apertures 21 are termed therein so that when the lianfie 1S) is prsitioned in abutting relation to the end c 13 ot' the armor 12 et a pair of conduitsi the wires 10 and their insulation 11 will extend through the apertures 21 in this flange or bushingl portion of the member and will hear against the smooth edges o1' the apertures rather than against the sharp edges ot the conduit armor which would damage the insulation. A central aperture Q2 is tornied in the member 16 through which the screw 15 may extend and in the present infince 'his aperture is elongated so as to permit the device to be easily manipulated when it is placed in position Within the box.

To assemble the box, the member lo is placed on the screw 15 andthe screw is threaded into position in the box. In this position the member 1li extends substantiallj.' parallel to the .intersection 7 ot the side and base walls and the clamping iiange 1S c:-;tends; down over the lnocl--out holes tl in one ot the walls while the bushing` tlangije 1D extends 'troni its poiny ot Contact with the screw 15 toward and into contact with the other of the walls ,so that when it is desired to insert a pair otl co2 luis through the lnloclr-out holes partially covered by said clampingy tlange 1S, it is ary to rotate the member 1.6i, .ut an ar i( l f dicular to the screw 1o and substant parallel to the intersection 7. The condui Sl are then inserted through the linee* holes 8 and the wires 10 with their insu 11 are inserted through the bushingA apertura:

21 in the bushing flange 19 and the conduits 5 are moved on into the box the ends ot the con-- duit armor 13 e' the bushingr danse 1E? and move the entire clamping and bushirff member 16 until it contacts the head o1 tirx screw 15. Durme,` this movement ot the menilil ber 16 the member is maintained in its proper position on the scr-ew through the cooperation of the aperture 22 and anotch 23 formed in the clamping iiange 1S midway between the two notches 20, this notch serving to engage the side of the screw 15 in certain positions of the member 1G.

The screw l5 is then tightened and in this operation the edge of the bushing flange 1Q which contacts the wall of the box is pressedl into firm contact with the wall and serves a pivot point about which the member may rotate. iis the screw 15 is further tightened, the entire member 10 will swing about this point and thus move the clamping flange 18 along the wall through which the conduits extend to clamp the conduits between the clainpin flange 18 and the opposite edges of the knochout holes. ln its clamping position the fla L 18 lies adjacent to the wall through which the conduits extend and serves to close the lrnocli'- out holes more completely about the conduits.

ln order to insure an. equal clamping action on each of the conduits a. narrow project'ng lip 2st is formed on the lower edge of the bushing lange 19 'for the purpose of providing a bearing against the wall of the box about which the member 16 may pivot in any direction and thus produce an equalized clamping action on the two conduits Thus it will be noted that the bushing flange 19 serves as means cooperatingl with one wall ot the box and with the screw 15 when it is tightened to cause clamping movement of the clamping fiange 18 along the other one of the walls.V

It will be noted that the clamping flange 18 engages andclamps the conduits at a point which lies a substantial distance from the end of the conduit armor12 so that the portion of the conduit lying between this point and the end of the conduit armor may be freely moved transversely of the axis of the conduit. Thus it will be apparent that in case a sharp `edge 13 of, the conduit is positioned in alinement vwith one of the bushing apertures 21 this sharp edge cannot cause damage to the insulation 11 when the wires 10 are moved transversely since suc 'trans verse movement of the wires will effect transverse movement of the end of the conduit until the wire 10 or its insulation 11 bears against the smooth edge of the bushing aperture 21.

It will also be noted that since the clamping and bushing member 16 is mounted wit-hin the box on the screw 15 which is substantially symmetrical with respect to the two intersecting walls and their lrnocleout holes,

this clamping and bushing member in ther out holes in either the side wall or the base wall.

From the :foregoing it will be apparent that the invention provides an outlet box which may be more economically manufac-m tured and assembled than those heretofore avilable'since it embodies a single sheet metal member which serves both for clamping and bushing the ends ot a pair of cables and which Y may be utilized with eqiialfacility for oper-"` f,

ating uponapair of conduits extending into the box through either of two intersecting walls.

I claim as my invention:

1. An outlet box having, iii combinationf-i a base wall and an intersecting side wall, each of said walls having a pair of knock-out holes formed therein ad] acent to their intersection and to each other, and a unitary device positioned within said box for clamping a pair of ,3

conduits entering the box through either of said pairs of knock-out holes and for bushing the ends of such a pair of conduits, said device comprising a substantially rigid meinber extending parallel to said intersection fio and formed from sheet metal to provide an apertured web with a clamping flange at one edge and a bushing flange at the other edge, said flanges being substantially parallel to each other, said clamping flange having z5 spaced notches formed at its edges to engage the sides ofa pair of conduits and said bushing flange having spaced apertures formed Vtherein through which wires may pass from said conduits into the center ofthe box, and m a screw for holding said member in said box and Jfor applying clamping pressure to said clamping flange, said screw extending through the aperture in said web and engag ing said box at an angle of substantially 45 1L.;

section of said walls, and a unitary device positioned within said b ox for clamping and bushing the ends of a pair of conduits enter- -ing the box through said knock-out holes, said device comprising an apertured substan-` i 1;;

tially rigid member extending parallel to said interseotioii, a screw for holding said inember in said box and for applying clamping pressure to the same, said screw extending through the aperture in said member and ifi engaging said box at an angle of substantial ly 45 to the walls thereof so as to substantially bisect the angle between said walls, said member being formed to provide a bushing portion extending from said screw toward iti and into contact with said side wall, a second port-ion extending from said screw substantially at right angles to said bushing sec'- tion toward the said bottom wall and having a clamping flange thereon adjacent said' bot-` if liti ` through which wires may pass from said conduits into said box, said clamping flange extend ing over the holes in said bottom wall so as to necessitate rotative movement about an axis perpendicular to said screw when a pair of conduits is inserted through said holes and being rotatable in a reverse direction by said screw to clamp such a pair of conduits.

3. An'outlet box having, in combination, a base wall and an intersecting side wall, each o't said walls having a pair ot adjacent knocksont holes formed therein adjacent to the inte section ot said walls, and a unitary device positioned within said box for clamping and bushing the ends of a pair oft conduits entering the box through said knockout holes, said device comprising an apertured suhstzmtially rigid member extending` parallel to said intersection, a screw lor holding` said member in :aid b x and for applyingclamping pressure to the same, said serew'extending through the aperture in said member and occupying a p 4,cion substantially bisecting the angle between the walls thereof, said member being formed to provide a bushin portion extending from said screw toward and into contact with one ot said walls, a second portion extending Atrom said screwI substantially at right angles to said bushing section toward the other oit said walls and having a clamping flange thereon adjacent said other wall with spaced notches formed at the edges ot said flange to the sides or a pair of conduits, said bushing flange having similarly spaced apertures lornied therein through which wires may pass from said conduits into the cent-er of the box, said clamping flange normally extending over the holes in said other wall so as to necessitate rotative movement about an axis perpendicular to said screw when a pair ot comV lits is inserted 'through said holes, and said member being rotatable about the axis ot said screw when it is loosened to position the member tor clamping and bushing a pair ot conduits entering either set of knock-out holes.

el. An outlet box having, in combination, two walls intersecting at substantially rial t angles, each of said walls having a pair of knock-out holes formed therein adjacent their intersection, a screw engaging said walls and occupying a position within said box subsdintially bisecting the angle between said wa ls` and member held in position Within said box by said screw, said member lia-ving means tor engaging a pair ot conduits er;- tending into the box through either set ot knock-out holes and also having means for bushing the ends oi such a pair ot' conduits, said conduit-engaging means maaien being arranged to be moved by said screw along the wall through which the conduits extend to clamp such conduits in position while the bushing means is clamped firmly in contact with the other of said walls.

5. An outlet box having, in combination, two walls intersecting at substantially right angles, each ot said walls having a pair ot knock-out holes formed therein adjacent their intersection, a screw engaging said walls and occupying a position within the box substantially bisecting the angle between said walls, and a. member held in position within said box by said screw, said member having means for engaging a pair ot' conduits extending into the box through either set ot knock-out holes and also having means for bushin the ends of such a pair ot conduits.

G. An outlet box having, in combination, a pair of intersecting walls, each of said walls having a knock-out hole formed therein, and a unitary conduit clamping and bushingdevice comp 'ising a screw engaging said box at the intersection of said Valls and occupying a position substantially bisecting the angle therebetween, and a substantially rigid member mounted on said screw and provided with bushing portion having an aperture through which wires may extend from an armored conduit into the center of the box, and means on said member operable when said member is moved in one direction by said screw to clamp such a conduit at a substantial distance i'rom the end thereoiz and from said bushing portion so as to permit i'ree ransverse movement ot the end of the conduit armor by the wires, said member being rotatable about the axis of said screw when loosened to adjust said member for clamjiing and bushing a conduit extending into said box through either knock-out hole.

7. An outlet box having, in con'ibination, a pair of intersecting walls, one of said walls having a pair of knock-out holes termed therein adjacent said intersection, a screw engaging said box at an acute angle to one olf said walls, and a` member positioned within said box and having an aperture therein through which said screw extends to support the member within the box, said member having a conduit engaging flange thereon with a notch formed therein arranged to cooperate with the side ot said screw to maintain the member in proper position within the box.

8. An outletbox having, in combination, a pair ot` intersecting walls, each of said walls having a knock-out hole formed therein adjacent their intersection, and a unitary device tor clamping and bushing the ends ot a conduit extending into the box through the knock-out hole in either of said walls, said device comprising a screw engaging said walls at their intersection and occupying a position within the box substantially bisecting the angle between said walls, and a second member loosely mounted on said screw to permit reversal of its position within the box, said member being formed from sheet metal to have substantially a U-shaped cross section, one side of said U being shorter than the other and serving as a conduit engaging and clamping portion, and the other side having an aperture formed therein through which a wire may extend into the center of the box, the smooth sides of said aperture serving as a bearing for the wire to prevent damage to its insulation.

9. An outlet box comprising, in combination, a pair of intersecting walls each of said walls having a pair oi' knock-out holes formed therein adjacent their intersection, a screw engaging said walls at their intersection and occupying a position substantially bisecting the angle between said walls, and a member having conduit engaging means mounted within said box and having an aperture formed therein through which said screw extends to maintain said member in position within the box, said member being freely movable about the axis of said screw to place said conduit engaging means in position to engage and clamp a pair of conduits extending into the box through the knock-out holes in either of said walls, said member having means formed integrally therewith and arranged to cooperate with one of said walls and with said screw when it is tightened to cause clamping movement of said conduit engaging means.

10. An outlet box having, in combination, a pair of intersecting walls, each of said walls having a pair of knock-out holes formed therein adjacent to their intersection and to each other, a screw engaging said walls at their intersection and occupying a position substantially bisecting an angle between the walls, and a sheet metal member positioned within said box and having an aperture formed therein through which ya screw extends to support the member within the box, conduit engaging means ormed on said niember at one edge thereof, means formed at the opposite edge oil said member 'for bushing the ends of a pair of conduits clamped by said member, a lip projecting from the edge of said bushing member to provide a pivotal bearing against one of the walls of said box, said member being shiitable about the pivot point formed by said lip as said screw is tightened to apply an equalized .clamping pressure through the medium of said conduit engaging means to a pair of conduits extending into the box through the other one ot said walls.

l1. An outlet box comprising, in combination, a pair of intersecting walls, one of said walls having a pair of knock-out holes therein adjacent their intersection, a screw engaging said walls and occupying a position in which it substantially bisects the angle between the walls, a member positioned within the box having an aperture formed therein through which said screw extends to support the member in said box, said member having conduit engaging means thereon normally positioned adjacent the wall having said knock-out holes therein, said member also having means formed thereon arranged to cooperate with the other one of said walls and with the screw when it is tightened to cause an equalized clamping of a pair oi1 conduits'extending into said box through said knock-out holes.

12. The combination of a forwardly opening outlet box formed by side and rear walls intersecting substantially at right angles to each other, said box having a pair of adjacent knock-out holes formed therein with their forward edges lying in one of said side Walls, a screw symmetrically positioned relatively to said two holes and engaging said box so as to occupy a position substantially bisecting the angle between said rear wall and the last mentioned side wall, and a sheet metal clamping and bushing member on said screw of substantially U-shaped cross section, one side of said U-member being engaged by said screw and having a pair of spaced bushing apertures therein through which wires may extend from a pair of conduits into the box, the other side of said U-meinber being formed to provide spaced notches to engage a pair of conduits extending through said pair of holes, said screw being operable to hold said other side of the U-nieinber snugly against said side wall and to move it along said side wall to clamp a pair of conduits extending into said box through said holes.

In testimony whereof, I have hereunto affixed my signature.

HERBERT RAY COOK.

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